Cooling apparatus



April 1944. M. P. WINTHER 2,345,850

COOLING APPARATUS Filed April 13, 1942 5 Sheets-Sheet l FIGI.

April 4, 1944. M. P. WINTHER COOLING APPARATUS 3 Sheets-Sheet 2 Filed Aptril 13, 1942 April 4, 1944. p wlNTHER 2,345,850

COOLING APPARATUS Filed April 15, 1942 3 Sheets-Sheet 3 FIGS.

Patented Apr. 4, 1944 2,345,850 l COOLING APPARATUS Martin P. Winther, Waukegan, Martin P. Winther, as

111., assignor to trustee Application April 13, 1942, Serial No. 438,787

5 Claims.

' This invention relates to cooling apparatus, and with regard to certain more specific features, to means for air-cooling eddy-current machines.

Among the several objects of the invention may be noted the provision of cooling means for eddy-current machines in which a high air-cooling efficiency is obtained substantially noiselessly; the provision of means for providing noiseless cooling which is of adequate capacity; and the provision of apparatus of the class described which is simple and economical to manufacture and operate. other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which are illustrated several of various possible embodiments of the invention,

Fig. 1 is a vertical section showing one form of the invention;

Fig. 2 is a vertical section of Fig. 1;

Fig. 3 is an enlarged detail Fig- 1; I

Fig. 4 is a view similar to Fig. 3, but showing a modification;

Fig. 5 is a View similar to Fig. 1, showing still another modification;

Fig. 6 is a detailed view of a and,

a Fig. '7 is an enlarged detail of certain peripheral grooves and teeth and a cooperating comb.

Similar reference characters indicate corresponding parts throughout the several views of the drawings.

In many smaller eddy-current machines, aircooling is feasible, and it is to these and the like that the invention is directed.

Referring now more particularly to Fig. 1, there is shown at numeral l a driving motor having a shaft 3 to which is keyed a spider 5 which supports a hollow inductive rotor cylinder l. At nutaken on line 2-2 of a portion of portion of Fig. 5;

meral 9 is the driven shaft which carries an armature H having radial teeth l3 and nested peripheral electric coils l5, piloted with respect to the armature I l by means of a pilot bearing ll.

The coils 15 are electrically energized from suitable slip rings iii, to provide toric flux fields which are concentrated by the teeth l3 and interlink the armature II and the inductor l.

The shaft 3 is The eddy currents in the inductor drum 1 produce heat which needs to be carried away. Here tofore various forms of fins on the outside of the drums such as l have been proposed. In general, I have found that axial fins are more costly to produce than peripheral fins, because of the milling operations required, but they have more capacity than peripheral fins. In addition the axial fins are noisy and special precautions need to be taken for introducing air into them if Windage noises are to be satisfactorily reduced. Even then, they are not as quiet as the means of the present invention.

Peripheral fins are cheaper to produce than axial fins since they may be made simply by a turning operation on a lathe, or the like, but such fins ordinarily do not move enough air to cause efficient cooling. The air forms a stagnant film between such fins. By means of the present invention, such peripheral fins are caused to move the requisite amount of air.

The invention consists in producing on the outside surface of the inductor drum 1 a plurality of adjacently located deep V-shaped grooves which produce intermediate peripheral V-shaped fins 2|. In the simplest form of the invention shown in Figs. 1-3, these fins are all of the same depth. Preferably, the surfaces of the fins are rough, or wavy in section, as indicated in Fig. 7. This effect may be produced during th machining operation. Thus the surfaces of the teeth tend frictionally to drag air around with them in the grooves between the teeth.

Then, in order to force the air to leave the spaces between the annular fins or ribs or teeth, I provide radially located combs 25, mounted on a support 23. As indicated in Fig. 2, these combs are plate-like, being mad for example of sheet iron, and are axially positioned at angular intervals. These combs have shapes complementary to the fins 2| and fit down into the grooves between fins fairly closely as indicated in Fig. 7.

I have found that a radial arrangement of the comb plates is best, because it permits of operating the machine in either direction and pro duces the best circulation of air, as indicated by the arrows in Fig. 2. The scooping action effected by non-radial combs is offset by dead-air pockets behind them. With radial combs, I have been able to project air radially out to a distance of 8 to feet under normal operations of these machines. This prevents the hot air from being immediately drawn back into the grooves on the other sides of the combs and therefore effects very eiiicient cooling.

By the use of V-shaped annular fins and complementary combs, noise is substantially reduced, because the cool air flows in'smoothly and unlformly behind each comb. It streamlines into the grooves between fins and hot air is swept out vigorously at the impact side of the combs. Here it is vigorously directed outwardly. There is no whipping or fanning action of the air by any multiplicity of axial blades, as in some former constructions.

It is usually advantageous to use more than two combs, although even one comb would be sufficient for conditions of moderate heat dissipa-\- tion. In the latter case, the cool air enters behind the comb and warm air is deflected off on the other side of the comb after a full circuit of the drum. In the case of a multiplicity of combs, cool air enters behind each comb and is deflected at the next comb, the action being repetitious within one revolution.

A number of combs is very desirable where larger amounts of energy are to be dissipated. The distance between the combs is adjusted so as to insure easy entrance of air, pick-up of the air, and deflection of it when it has obtained a temperature of the order of 100-180" F.

In Fig. 4, like numerals designate like parts. In this embodiment, the depth of the grooves, and consequently the height of the fins 2 I, is variable. As is known, the production of heat in an eddy-current drum takes place where the eddy currents occur which is where the flux is concentrated. Therefore, it is desirable that the heat-dissipatin fins 2| be directed down to the region where the eddy currents occur; but no further, so as not to remove iron needed for flux passage. If this flux-containing region is not fiat, but has some curvature, then the grooves and fins ar brought about down to that curvature, as indicated in Fig. 4, for example, where the coil I5 produces the magnetic field indicated by the dotted lines.

Figs. 5 and 6 show a multi-coil machine in which the polarities of the coils are of the character to produce the magnetic fields indicated in the dotted lines. Such fields provide heating re gions in the inductor which are of similar shape. Thus it is desirable that the depths of the grooves vary up and down along the length of the drum as indicated, to follow this shape more or less.

In th machine shown in Figs. 5 and 6, like numerals designate like parts, but in this case,

since the inductor drum 1 requires an additional head 29, an additional pilot bearing 3| is used.

As indicated, in this case the depths of the various grooves are grouped so as to provide for example, starting from the left in Fig. 6, first three deep fins 33, then three medium depth fins 35, and then four short fins 31; then again three medium depth fins 35; and finally two deep fins 33. The series is then repeated for each coil l5. The purpose of having everal fins of the same depth is to provide for simplifying cutting of the grooves. This causes the successive groups of fins to reach down to the eddy-current region which is satisfactory enough for all practical purposes.

The combs which are renumbered as 39 in Figs 5 and 6 have teeth of complementar shape. The

functions are analogous to those already described.

From the above, it will be seen that, by means of the V-shaped fins which are rather siinple to produce, there is obtained an air cooling means which is quiet, since the air streamlines down into the V-shapecl grooves over the more or less pointed teeth, and then streamline out again very quietly, but vigorously. The temperature may be controlled in accordance with the various capacities which may be expected of various machines by altering the spacing and number of combs.

It is desirable that the teeth of the combs fit the grooves on the rotor as closely as is mechanically feasible without friction.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. In an eddy-current machine, a rotary field member, a rotary armature drum cooperating therewith, at least one field coil on the field member providing flux interlinking th field member and the drum according to a certain pattern, said drum having spaced peripheral grooves of depths to provide spaced teeth which reach practically down to the pattern engendered by said flux to dissipate eddy-current heat from said pattern, and at least one comb having spaced teeth complementary to said grooves and extending therein for wiping out warm air from the grooves in the drum.

2. In an eddy-current machine, a rotary field member, a rotary armature drum cooperating. therewith, at least one field coil on the field member providing flux interlinking the field member and the drum according to a certain pattermgsaid drum having spaced peripheral grooves of depths to provide spaced teeth of various lengths which reach practically down to the pattern engendered by said fiux to dissipate eddy-current heat from said pattern, and at least one comb having spaced teeth complementary to said grooves and extending therein for wiping out warm air from the grooves in the drum, said grooves in the drum being V-shaped opening outward.

3. In an eddy-current machine, a rotary field member, a rotary drum cooperating therewith, field coils on the field member providing a toric flux field interlinking the field member and the drum, spaced peripheral grooves around said field in the drum and having a depth to provide spaced teeth of length reaching substantially down to the fiux field region, and a plurality of combs having spaced teeth complementary to said grooves in the drum and extending therein for wiping out warm air from the grooves, the fins on the inductor drum being tapered down outwardly toward a point whereby streamlined flow of air into and from between the teeth on the drum is accomlished.

4. In eddy-current apparatus, a field member having a plurality of spaced peripheral coils, a drum surrounding said armature, said coils engendering a flux field of varying depth throughout the drum, and peripheral cooling fins formed by grooves on the drum having depths substantially according to the outlines of the flux field in said drum, and complementary combs in th grooves to sweep out air.

5. In eddy-current; apparatus, a field member having a plurality of spaced peripheral coils, a drum surrounding said armature, said coils engendering a flux field of varying depth throughout the drum, peripheral cooling fins formed by grooves on the drum having depths substantially according to the outlines of the flux field in said drum, and at least one radially positioned comb having a shape complementary to the cross section between said fins and closely co-operating with the grooves.

MARTIN P. WHTTI-IER. 

